The ESP Offline Programmer is an ESP32 board with a microSD card slot designed to flash the firmware to other ESP32 or ESP8266 modules without a PC. You’ll still need one to copy the firmware to a microSD card, but once it’s done you can just insert the microSD card into the board and after wiring is done ideally using a jig, start the flashing sequence with the press of a button.
In some ways, it’s the hardware equivalent of the esptool utility and can be useful for remote deployment where carrying a laptop may not always be convenient and potentially for flashing hundreds or thousands of modules using multiple ESP Offline Programmers in a way that’s faster than using computers.
ESP Offline Programmer specifications:
- Wireless module – Espressif Systems ESP32-WROOM-32E
- ESP32 dual-core Tensilica LX6 microcontroller
- Storage – 4MB flash
- Wireless 2.4 GHz WiFi and Bluetooth LE connectivity, built-in PCB antenna
- Storage – MicroSD card slot
- USB – USB Type-C port for power and programming the built-in ESP32-WROOM-32E module
- Target module connection
- CH340C USB to serial chip to communicate with target ESP32 or ESP8266 module
- 6-pin header with Tx/Rx, DTR/RTS for automatic bootloading (control GPIO0 and EN pins of ESP32/ESP8266), 3.3V, and GND
- Misc
- Boot button for the built-in ESP32
- Reset and Upload buttons
- 3x status LEDs
- Power Supply – 5V via USB-C port
- Dimensions – TBD
The ESP32 or ESP8266 module needs to be wired as shown above. Connecting wires directly to the module would defeat the purpose of having an easy-to-use firmware flashing solution, so techiesms has made some programming jigs for ESP32-WROOM-32 and ESP8266 modules. Note these programming jigs are not exactly new and you’ll find plenty on Amazon, AliExpress, or other shops from various vendors
The project is partially open-source with the PDF schematics, necessary components, and instructions available on Hackster.io and the Arduino firmware for ESP8266 and ESP32 module flashing on GitHub. The firmware is based on Espressif’s own esp-serial-flasher code allowing other microcontrollers (STM32, ESP32 Series, Any MCU running Zephyr OS, and Raspberry Pi Pico) to flash ESP32 modules or boards.
The video below explains how the project was created and how to use it.
The ESP Offline Programmer can be purchased for 1,499.00 (or about $17.5 US) and the programming jigs for ESP32 and ESP8266 modules for 465.25 ($5.5) each. Sadly, it looks like they only ship locally to India. You may be able to use another ESP32 board with a microSD card and user buttons, plus a CH340C breakout board to reproduce a similar setup. Alternatively, MeatPi Electronics is about to launch a similar product called ESP Offline Flasher via Crowd Supply that will ship worldwide.
Via LamLoei Club Facebook group
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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